Manually operable cutting device particularly for films



May 13, 1969 3,443,314

MANUALLY OPERABLE CUTTING DEVICE PARTICULARLY FOR FILMS L.,KARL ET AL Filed April 12, 1967 m r 9 k A 6 31 2 R 5 2 I6 u F m /7 E: v H

, b 2 5 w W 7 3 I lnven tor: WK 7 U.S. Cl. 30-237 United States Patent O Int. (:1. inch 3/00 8 Claims ABSTRACT OF THE DISCLOSURE A manual cutting device particularly for thin and tenacious film comprising two pivotally and slidably attached knife levers each carrying a cutting face at their adjacent free end, a spring urging the cutting faces towards each other, one of the knife levers is pivotally attached to a support lever at a point remote from the joint between the two knife levers.

Field of the invention This invention relates to a manually operable cutting device, particularly adapted for rounding the corners of sheets of X-ray film.

Prior to placing sheets of X-ray film in at protecting envelope, it is advantageous to round their sharp corners in order to facilitate their insertion into the envelope and avoid damage thereto. Also, as the corners are rounded, small perforations caused by pins disposed in the X-ray developing frames for fixedly holding the X-ray film are cut off. Such perforations, if left in the film, would scratch the emulsion of other film when stored in a stack.

Description of the prior art There are a plurality of known cutting devices for the aforenoted purpose; some are exclusively grip-type tools and some may be secured to a table and provided with power means such as an electric motor or a magnet. The known manually operable cutters usually comprise two pivotally connected simple sheet metal plates each comprising a cutting edge. The plates, which are usually biased open, have a fixed pivotal axis. If no particular care is taken when making the cutting edges, it is from the start questionable whether a through-out clean cut may be obtained.

When X-ray film of the celluloid type is used, the aforenoted irregularity has not been disturbing since this film material has a low tenacity and the film sheets are relatively thick. More recently, however, X-ray film is made of a polyester basis which is substantially more tenacious and the sheets are thinner. This new film material is difiicult to cut with the known cutting devices and in particular difficulties have been experienced in obtaining a smooth cut edge.

Summary of the invention In order to obviate the aforenoted disadvantages, it is a principal object of the invention to provide an improved cutting device which may be used as a grip-type tool or may be attached to a support that ensures a smooth cut through thin, tenacious material.

Briefly stated, the improved cutting device comprises two cooperating cutting edges each secured at one end of two knife levers which, at their other end, are pivotally and slidably secured to allow a relative displacement thereof in their longitudinal direction transversely to the cutting edges and wherein the two cutting faces are urged Patented May 13, 1969 towards one another by a spring acting in a direction of free movement of the pivotal joint.

The invention will be better understood and further objects and advantages will become more apparent from the detailed specification of one preferred embodiment taken in conjunction with the drawings.

Brief description of the drawings FIG. 1 is a sectional elevational side view of the novel cutting device in an open position;

FIG. 2 is an elevational side view of the same embodiment in a closed position;

FIG. 3 is a top plan view of the same embodiment in a closed position; and

FIG. 4 is an end elevational view of the same embodiment in a closed position.

Description of the embodiment As best seen in FIG. 1, the novel cutting device comprises a support lever 1, a lower knife lever 2 carrying a lower knife blade 3, and an upper knife lever 4 carrying an upper knife blade 5. All three levers 1, 2 and 4 may be stamped from sheet metal and bent to a U-shaped cross section defining a base and parallel sides extending normal to the base. The width of these levers is designed in such a manner that lever 2 fits into lever 4 while the latter, in turn, fits into support lever 1.

The base 1a of the support lever 1 is provided with mounting openings 6 for securing the device to a support (not shown). Basically, however, the levers are interconnected in such a manner that they may be operated by gripping the device similarly to plier-type tools. Extending between the upstanding sides of support lever 1 and secured thereto is a first pin 7 to which there is pivotally attached the upper knife lever 4 by means of two projections 8 extending from the opposed sides of lever 4. At the right end of the upper knife lever 4 there is secured to its sides a transversely extending second pin 9 which projects through slots 10 of the sides of the lower knife lever 2. Due to the securing means 9, 10, the two knife levers 2 and 4 may, in addition to a relative pivotal motion, shift in a longitudinal direction with respect to one another. Projections 11 of the sides of the lower knife lever 2 carry a roller 12 which may roll along the upper face 3 of base 1a of support lever 1.

The lower knife lever 2 carries at its left end a lower knife blade 3 secured to the lever by means of screw 14 and adjustable by screw 15. The blade 3 is, at least at its mid portion, slightly upwardly bent (FIG. 4) and has an arcuate convex cutting face 16 (FIG. 3) having an upper cutting edge 17. The upper, substantially planar knife blade 5 has a complemental concave cutting face 18 having a lower cutting edge 19. It is thus seen that while the complemental cutting faces 16 and 18 are adapted to be in a face-to-face contacting relationship when the device is in a position shown in FIGS. 2P4, the cutting edges 17 and 19 are so disposed that they are convergent towards their center and, consequently, divergent towards their ends. The purpose of this arrangement will become apparent as the specification progresses. At its opposed ends the blade 5 is provided with two lateral downwardly directed flanges 20 which, even in the open position of FIG. 1, are in engagement with the cutting face 16 of the lower knife blade 3. The knife blade 5 is attached to the upper knife lever 4 by means of a backwardly directed integral extension 22 which is secured to the lever 4 by means of screws 22.

To screw 15 and pin 9 there is secured a tensioned coil spring 23 which draws the two cutting faces 16 and 18 along their plane towards one another to hold the cutting clearance between these faces at a minimum and to ensure during operation, a continuous self-sharpening of the cutting faces. To the right end of the lower knife lever 2 there is further attached by means of rivets 24 a leaf spring 25, the free end of which engages the upper knife lever 4 to urge the two knife levers into a rotary opening movement about pin 9. The amplitude of the pivotal motion from the closed position shown in FIG. 2 to the open position shown in FIG. 1 of the two levers 2 and 4 is limited by the abutment of edges 26 of the sides of lower knife lever 2 against the pin 7.

The unit, basically comprising levers 2 and 4, may be pivoted counter-clockwise about pin 7 from its position shown in FIG. 1 whereby the roller 12 would lift from the surface 13. Normally, however, the roller 12 is in engagement with the surface 13 of base 1a of support lever 1.

The novel cutting device operates as follows:

The corner of an X-ray film is inserted between the two knife blades 3 and until the edges of the film abut against the downwardly bent flanges 20 of the upper blade 5. The levers 1 and 4 are pressed together either by a gripping motion or by pushing the upper cutting lever 4 towards the support lever 1 secured to a support. During this motion first the upwardly bent middle portion of the cutting edge 17 of the lower knife blade 3 cuts into the film. During further pivotal movement of levers 2 and 4 towards each other, the film is exposed to a tensioning force between two cutting locations moving outwardly from the center of the interengaging cutting edges 17 and 19. As a result, the film is cut from the inside outwardly toward its edges. During the cutting operation, as roller 12 shifts to the left, the lever advantage constantly increases resulting in a progressive increase of the cutting force.

The two knife levers 2 and 4 are centered with respect to the arches of the two cutting faces 16 and 18 and particularly between the downwardly bent flanges 20 of the upper knife 5. With respect to other parts of the device the levers may have a substantial lateral play. The self-centering of the levers contributes to the feature of holding the effective cutting clearance at the smallest possible value. The necessary equalizing motions may be taken up by the pivotal and sliding joint 9, 10.

The transitions between the base and sides of at least the exposed levers 1 and 4 are rounded so that the device is adapted to be held with a comfortable grip.

It is to be understood that a number of structural changes may be made in the above-described cutting device without departing from the spirit of the invention. Thus, for example, instead of the pin and slot joint 9, 10, other types of joints, such as an eccentric may be used. Further, roll 12 may be replaced by an articulated lever disposed between parts 1 and 2 and it is further feasible to form the cutting edges directly on levers 2 and 4 instead of using separate knife blades. Also, spring 23 may be attached to another part of lever 4 instead of pin 9.

What is claimed is:

1. A manual cutting device for rounding corner portions of a sheet, said device including a pair of pivotally interconnected knives biased open by resilient means, the improvement comprising,

(A) a first and a second elongated knife lever,

(B) a joint securing said knife levers together at one end, said joint allowing a pivotal motion and a linear sliding motion of said knife levers with respect to one another,

(C) a first and a second cutting face each having a 4 cutting edge cooperating with each other, said first and second cutting face carried at the end of said first and second knife levers, respectively, remote from said joint, said faces being disposed substantially parallel to one another and having an armate, mutually complemental configuration,

(D) two spaced dependent flanges constituting a continuation of one of said cutting faces and being in continuous frictional contact with the other of said cutting faces, and

(E) spring means acting along the path of said sliding motion and urging said flanges into said frictional contact.

2. A device as defined in claim 1, wherein said cutting edges are convergent towards their center and divergent towards their ends for cutting said sheet from its inside outwardly when said levers are caused to pivot against said resilient means.

3. A device as defined in claim 1, wherein said spring means is a tension spring, the ends of which are secured to said first and second knife levers, respectively.

4. A device as defined in claim 3, wherein said joint includes a pin fixedly secured to one of said levers and a slot provided in the other of said levers, said pin extending into said slot and adapted to be displaced therein along the length dimension of said slot.

5. A device as defined in claim 4, wherein one end of said spring is attached to said pin.

6. A device as defined in claim 1 including (A) a support lever,

(B) a pivot securing said first knife lever to said support lever at a location spaced from said joint, said pivot allowing a pivotal motion between said first knife lever and said support lever, and

(C) means secured to said second knife lever adapted to engage said support lever to cause a pivotal motion of said knife levers towards each other about said joint when said first knife lever is pivoted towards said support lever about said pivot.

7. A device as defined in claim 6, wherein said support lever and said knife levers extend in the same longitudinal direction, all of said levers have a U-shaped cross section of different widths, said second knife lever is receivable to nest in said first knife lever, and said last named knife lever is receivable to nest in said support lever.

8. A device as defined in claim 6, wherein said means adapted to engage said support lever includes a roller moving on said support lever towards said pivot when the knife lever secured to said support lever is pivoted theretowards.

References Cited UNITED STATES PATENTS 846,924 3/1907 Kampfe 30234 X 1,506,135 8/1924 Raschick 30131 X 2,146,196 2/1939 Shull 30229 2,548,392 4/1951 Radman 30-l3l 2,556,819 6/1951 Musselwhite 30229 3,050,853 8/1962 Domeny 30131 X 3,225,441 12/1965 Myers 3023l ROBERT C. RIORDON, Primary Examiner. I. C. PETERS, Assistant Examiner.

US. Cl. X.R. 30229, 253 

